It is known that chains of this type are made up of cylindrical helix-shaped links of a length slightly less than two loops and of a pitch approximately equal to a double thickness of the thread from which they are formed. At present, these chains are formed by manually linking, that is, connecting the links manually two-by-two through a spiral rotation of a link over a closed link already connected to the others. It is evident that the manual formation of these chains is time consuming and needs a great deal of attention and care by the operator. As above mentioned, these links are joined together by hand, that is, they are united between them two-by-two by a helicoidal rotation of a loose link with respect to an already closed link already linked to the others, thereby carrying out, alternatively, a free connection and a fixed connection, that is a so-called "Garibaldi module".
It is evident that the manual formation of such chains needs a lot of time as well as a great skill and care by the operator. As a consequence, the production of these chains is limited and their cost is so high that they are usually made only of precious metal such as gold and silver.